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<head>
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    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script type="text/javascript">
        var collection = {
    "1275":{
        "album":"依然范特西",
        "artist":"周杰伦",
        "tracks":[
            "听妈妈的话",
            "千里之外"
        ]
},
    "2468":{
        "album":"西界",
        "artist":"林俊杰",
        "tracks":[
            "西界",
            "杀手"
        ]
},
    "3245":{
        "artist":"许嵩",
        "tracks":[ ]
    },
    "5439":{
        "album":"遇见"
    }
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// 1.定义方法更新记录:
// function updateRecords(id,prop,value)
// 要求：
// 1).如果传入的value是一个空值，表示将该属性删除
// 2).传入的prop如果是tracks，则代表添加，其他是修改


// 3245 tracks '有何不可'
// 3245 tracks ''   -->删
// 5439 artist '孙燕姿'
// 5439 album '逆光'

function updateRecords(id, prop, value) {
            if (value != '') {
                if (prop == 'tracks') {
                    collection[id][prop].push(value);
                } else {
                    collection[id][prop] = value
                }
            } else {
                delete collection[id][prop]
            }
        }
        console.log(collection);



    </script>
    
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